security

ICCID activation was once a common workaround for carrier-locked iPhones. Apple patched it, so it cannot issue new unlocked tickets, but tickets created before the patch still work. To preserve an existing unlock through a reset, downgrade, or DFU restore, back up the activation ticket first and restore it afterward. The ticket is tied to one device and cannot be transferred. I use my iPhone 5s (A1453, au/KDDI Japan) as the example.

ACME is the protocol for automated certificate management. Let's Encrypt speaks ACME. Certbot is the official ACME client from EFF. This guide covers Certbot with Cloudflare DNS validation.

A container is not a virtual machine. VMs emulate hardware and run a full OS kernel. Containers share the host kernel and isolate processes using namespaces (which partition what a process sees: filesystem, network, PIDs, users) and cgroups (which cap what it uses: CPU, memory, I/O).